Journal of Hazardous Materials 416 (2021) 126162 Available online 21 May 2021 0304-3894/© 2021 Elsevier B.V. All rights reserved. Removal of ethyl acetate in air by using different types of corona discharges generated in a honeycomb monolith structure coated with Pd/γ-alumina Van Toan Nguyen a , Duc Ba Nguyen a , Young Sun Mok a, * , Md. Mokter Hossain a , Shirjana Saud a , Kyeong Hwan Yoon a , Duy Khoe Dinh b , Seungmin Ryu c , Hyeongwon Jeon c , Seong Bong Kim c a Department of Chemical and Biological Engineering, Jeju National University, Jeju, Republic of Korea b Department of Industrial Plasma Engineering, Korea Institute of Machinery and Materials, Daejeon, Republic of Korea c Institute of Plasma Technology, Korea Institute of Fusion Energy, Jeollabuk-do 54004, Republic of Korea A R T I C L E INFO Editor: Dr. H. Zaher Keywords: Honeycomb catalyst VOCs removal Corona discharge Ethyl acetate removal ABSTRACT A method based on the corona discharge produced by high voltage alternating current (AC) and direct current (DC) over a Pd/γ-Al 2 O 3 catalyst supported on a honeycomb structure monolith was developed to eliminate ethyl acetate (EA) from the air at atmospheric pressure. The characteristics of the AC and DC corona discharge generated inside the honeycomb structure monolith were investigated by varying the humidity, gas hourly space velocity (GHSV), and temperature. The results showed that the DC corona discharge is more stable and easily operated at different operating conditions such as humidity, GHSV, and gas temperature compared to the AC discharge. At a given applied voltage, the EA conversion in the DC honeycomb catalyst discharge is, therefore, higher compared with that in the AC honeycomb catalyst discharge (e.g., 96% of EA conversion compared with approximately 68%, respectively, at 11.2 kV). These new results can open opportunities for wide applications of DC corona discharge combined with honeycomb catalysts to VOC treatment. 1. Introduction The abatement of volatile organic compounds (VOCs) from the air is one of great interest in the feld of air pollution control (He et al., 2019; Zhu et al., 2017a; Veerapandian et al., 2017; Zheng et al., 2014). Ethyl acetate (EA) is a typical VOC and is widely used as a solvent in the chemical industry, ascendant, and a stable acid ester. EA is also used as an organic raw material and a solvent for coatings and plastic. EA is highly toxic and exposure to this VOC even at low concentrations can cause nausea, dizziness, and even cancer (Zhu et al., 2017a, 2017b). To date, many technologies such as thermal incineration (Tomatis et al., 2016), catalytic oxidation (He et al., 2019; Ostrovsky et al., 2017; Kajama et al., 2015), adsorption (Hsu and Lin, 2011; Boulinguiez and Cloirec, 2010), biological treatment (Wang et al., 2010), non-thermal plasma (NTP) (Talebizadeh et al., 2014; Xiao et al., 2014), and non-thermal plasma-catalytic oxidation (Nguyen et al., 2020b; Sultana et al., 2015; Vandenbroucke et al., 2011) have been employed to remove low concentration VOCs in large volume waste gas streams. Among these technologies, NTP catalytic oxidation techniques are considered to be more effective than the others because of their simple operational procedure and economic viability in industrial applications while most of the other technologies face diffculties such as high in- vestment, high-temperature requirement, incomplete degradation, slow reaction rate, and so forth (Nguyen et al., 2020b; Vandenbroucke et al., 2011; Lu et al., 2019). The Plasma-catalysis system combines the ad- vantages of high selectivity from the catalysis and rapid reaction rate from the NTP (Nguyen et al., 2020b; Hossain et al., 2021; Whitehead, 2010). The catalyst can solve the problem related to the formation of unwanted byproducts while the plasma makes up for the weak points of the catalyst such as deactivation and low activity at low temperatures (Nguyen et al., 2020b; Mok and Kim, 2011; Jia et al., 2018). The main technical challenges for the treatment of VOCs by using a plasma catalytic system in industrial applications are the generation of large volumes of homogenous and stable plasma inside a honeycomb catalyst under atmospheric pressure (Mizuno, 2013; Hensel et al., 2008; Sato et al., 2009). Discharge plasma in honeycomb catalyst can be produced by dielectric barrier discharge (DBD) (Reactor et al., 2002; Ayrault et al., 2004; Trinh and Mok, 2014), and corona discharge (Hossain et al., 2021; Nguyen et al., 2020a). Although DBD reactor can generate a stable/effective discharge plasma, it is diffcult to be * Corresponding author. E-mail address: smokie@jejunu.ac.kr (Y.S. Mok). Contents lists available at ScienceDirect Journal of Hazardous Materials journal homepage: www.elsevier.com/locate/jhazmat https://doi.org/10.1016/j.jhazmat.2021.126162 Received 1 February 2021; Received in revised form 6 May 2021; Accepted 16 May 2021